This invention relates generally to safety syringes, and more specifically to a safety syringe apparatus and method for injecting fluid from a syringe and subsequently automatically and immediately retracting a hollow needle permanently and protectively within the syringe body after a single use.
In recent years, the public has become increasingly aware of the health hazards associated with needle reuse and accidental needle prickings. This is true, especially among drug addicts, drug users (e.g., diabetics), medical personnel and healthcare providers. More than twenty blood-borne pathogens can be transmitted by the reuse of needles or accidental needle prickings, just a few of which include human immunodeficiency virus (HIV), acquired immunodeficiency syndrome (AIDS), hepatitis B, hepatitis C, syphilis, malaria, tuberculosis, and herpes.
The problem of spreading blood-borne pathogens through the reuse of needles is significant among drug addicts unwilling or unable to pay for sterile needles. The United States government, having recognized and acknowledged this problem, has attempted to control the reuse of syringe needles among drug addicts by establishing needle exchange programs where drug addicts can obtain free sterile needles in exchange for their contaminated needles. Despite this effort, at least 36% of HIV/AIDS cases and more than 50% of hepatitis B and hepatitis C cases in the United States can be linked to the sharing of needles among drug addicts. With approximately one million people with HIV/AIDS, more than 1.25 million hepatitis B carriers and more than 3.5 million hepatitis C carriers in the United States, the need to curb the practice of sharing needles is great. With more than 1.3 million injection drug users in the United States, the need for syringes having an integral, unremovable and unoverridable safety feature that limits the syringe to only a single use is overwhelming. (tri-ject.net/stats.html).
In addition, the spreading of blood-borne pathogens through the reuse of contaminated needles by drug addicts, drug users, medical personnel and healthcare providers in other countries throughout the world is becoming increasingly prominent. For example, approximately 30% of reported HIV/AIDS cases in Brazil, Chile, Uruguay, Paraguay and Argentina are directly related to the sharing of contaminated needles among drug addicts. Nearly 74% of injection drug addicts in Spain are HIV infected. Approximately 70% of the HIV cases reported in China are directly linked to the sharing of contaminated needles. In eastern European countries, 80% of injection drug addicts admit to sharing contaminated needles. Approximately 43% of the HIV/AIDS cases reported in Poland and Yugoslavia are linked to the sharing of contaminated needles among drug addicts. Furthermore, It is estimated that approximately 22 million people worldwide are living with HIV or AIDS. Unfortunately, in many countries, especially third world countries, sterile syringes are simply unavailable due to economic reasons. (www.vanishpoint.com/needlestick.html).
Although approximately one million accidental needle prickings are reported by healthcare workers annually, at least three million accidental needle prickings occur each year that subsequently go unreported. Various studies estimate that out of all the needle pricking injuries that occur to nurses, approximately 40% to 53% go unreported. Various studies also estimate that out of all the needle pricking injuries that occur to laboratory technicians, approximately 92% go unreported. Various studies further estimate that out of all the needle pricking injuries that occur to physicians, approximately 70% to 95% go unreported. (www.osha-slc.gov/SLTC/needlestick/saferneedle devices/saferneedledevices.html).
In 1997, the Centers for Disease Control and Prevention (CDC) sponsored a study which found that approximately 76% of needle pricking injuries could be avoided by using safety needles. As a result, needle legislation has now been introduced in approximately twenty-five states and in the District of Columbia. In fact, such safety needle legislation has already been signed into law in a number of states including California, Texas, Tennessee, New Jersey and Maryland. In addition, the Occupational Safety and Health Administration (OSHA) has promulgated a Blood-borne Pathogens Standard requiring employers to evaluate the effectiveness of existing controls designed to minimize or eliminate employee occupational exposure and to review the feasibility of instituting more advanced controls. Furthermore, the Food and Drug Administration (FDA), in an effort to protect health care workers, has set forth guidelines suggesting specific features that a safety syringe should possess. These include a safety feature that is not only simple and self evident to operate, thus requiring little or no additional training to use effectively, but also a safety feature that is an integral part of the apparatus. In other words, the guidelines suggest that the safety feature itself be unremovable and utilization of the safety feature be unavoidable. (www.osha-slc.gov/SLTC/needle stick/saferneedledevices/saferneedledevices.html; www.seiu.org).
As a result of the foregoing state legislation and agency guidelines, a great amount of time, effort and money has been invested by syringe manufacturers in developing syringes with safety needle designs. Presently, there are at least 250 types of safety syringes. However, the safety syringes that currently exist have been criticized for generally being too expensive to manufacture and having a safety feature that is not an integral part of the safety syringe. Another criticism includes safety syringes that are not economically feasible because operation of the safety feature is not self evident and therefore additional training is required to use the apparatus effectively. Additionally, the safety feature of at least one safety syringe is simply ineffective at preventing the transmission of blood-borne pathogens due to xe2x80x9crefluxxe2x80x9d blood contamination.
Of the current safety syringes, safety syringes using a spring mechanism are the most common for automatically retracting a hollow needle after injecting a fluid. However, these safety syringes are typically more expensive because of the required incorporation of additional materials for manufacture. Standard or conventional hypodermic needle syringes typically cost from five to seven cents each. On the other hand, the median increase in cost for a safety syringe is approximately thirty cents or more. At first glance, this minimal cost increase does not seem significant. However, after considering the thousands, if not millions, of needles used each year, the resultant increase in annual cost for utilizing the more expensive safety syringe is unfortunately excessive.
Another type of safety syringe is a syringe using a protective shield that slides and locks over the needle to protectively encase the piercing tip. However, the protective shield is not an integral part of the safety syringe. Because the protective shield slides manually over the needle, this safety feature may be overridden by a person who inadvertently or purposely fails to slide the shield over the needle thereby exposing a contaminated and potentially infectious piercing tip. Additionally, the protective shield requires two hands to slide the shield over the needle to encase the syringe needle. As a result, a person""s hands may slip while sliding the shield and subsequently be pricked with the exposed and contaminated piercing tip.
Another type of safety syringe is a needleless jet injector that shoots a pinpoint jet of fluid through the skin at extremely high velocities. However, this safety syringe is not economically feasible because operation is not self evident and, therefore, costly time consuming training is required to use the apparatus effectively. Additionally, the needleless jet injector has been linked to causing hepatitis B infections resulting from xe2x80x9crefluxxe2x80x9d blood contamination of the injector heads from the previous injection. One approach is to provide proper cleaning and maintenance of the injector heads between injections, however this is time consuming and is not failsafe at preventing subsequent transmission of infectious blood-born pathogens. Another approach is to provide needleless jet injectors with nozzles and fluid chambers that can both be discarded after each injection. However, these safety features are mere accessories to, and are not built-in as integral parts of the apparatus. Therefore, the safety features of the needleless jet injector could be removed or even overridden by not utilizing a sterile, unused nozzle and/or fluid chamber attachments.
Therefore a need exists for an effective and efficient, inexpensive safety syringe that is simple and self evident to operate and integrally comprises a safety feature having a hollow needle that protectively retracts automatically after a single injection. Further needed is a safety syringe that alleviates needle reuse and accidental needle prickings with contaminated syringe needles and therefore ultimately assists in preventing the transmission of blood-borne pathogens such as HIV/AIDS, hepatitis B and hepatitis C via contaminated syringe needles.
The present invention is a safety syringe apparatus and method for injecting fluid from a syringe and subsequently automatically and immediately retracting a hollow needle permanently and protectively within the syringe body after a single use. The present invention prevents needle reuse and accidental needle prickings with contaminated syringe needles.
The invented apparatus includes a syringe body having a plunger and a needle body, both of which are slidably disposed and partially positioned within the syringe body. The syringe body includes a shaft seal at a first end of the syringe body and a variable vacuum compartment. The plunger includes a shaft, a piston seal attached proximally to one end of the shaft and a punch located at the end of the shaft. The shaft of the plunger is slidably engageable with the shaft seal of the syringe body. The piston seal of the plunger is slidably disposed within the syringe body. The syringe body between the shaft seal and the piston seal defines the variable vacuum compartment. The needle body is temporarily attached to a second end, opposing the first end, of the syringe body and includes a piercing tip end attached to a ferrule.
During an injection stroke of a single injection of fluid, a vacuum is created within the variable vacuum compartment as a result of an increase in volume within the variable vacuum compartment without a corresponding influx of air molecules and fluid molecules into the variable vacuum compartment, due to the shaft seal and the piston seal being substantially air tight and fluid tight. At the end of the injection stroke, the punch frictionally engages the ferrule. The needle is immediately and automatically withdrawn within the syringe body as a result of the vacuum created within the variable vacuum compartment during the injection stroke. The needle body is withdrawn into the syringe body such that the piercing tip end permanently resides enclosed within and protectively pressed against the syringe body. This alleviates needle reuse and accidental needle prickings and, therefore, ultimately prevents the transmission of blood-borne pathogens and other diseases by contaminated syringe needles.
The invented safety syringe apparatus is efficient and effective at preventing the transmission of blood-borne pathogens and other diseases through needle reuse or accidental needle prickings with contaminated syringe needles. The safety syringe is also inexpensive to manufacture relative to the cost of manufacturing standard or conventional hypodermic needle syringes. In addition, the safety feature of the invented apparatus is simple and self evident to operate and therefore requires no additional training to use the apparatus efficiently and effectively.
This safety feature is an integral part of the invented safety syringe apparatus, meaning that the safety feature is built-in as a necessary, inherent and integral part of the apparatus. Because this safety feature is not a mere accessory which might be removed, circumvented or overridden after a single use, the piercing tip end permanently resides enclosed within and protectively pressed against the syringe body therefore providing a protective barrier between the person""s hands and the contaminated needle. Furthermore, this safety feature goes into effect automatically and immediately after a single use and remains in effect during disposal, thus alleviating needle reuse and accidental needle prickings with contaminated syringe needles. Therefore, the safety feature ultimately prevents the transmission of blood-borne pathogens such as HIV/AIDS, hepatitis B, hepatitis C and other diseases by needle reuse and accidental needle prickings with contaminated syringe needles.
The principal object of the present invention is to provide an automatically retractable needle safety syringe apparatus that injects fluid from a syringe and subsequently automatically and immediately retracts the piercing tip end of a hollow needle permanently within the safety syringe body, protectively pressed against the inner surface of the tube, after a single use thus preventing the transmission of blood-borne pathogens, such as HIV/AIDS, hepatitis B, hepatitis C and other diseases, via needle reuse and accidental needle prickings with contaminated syringe needles.
Another object of the present invention is to provide a method of automatically and immediately retracting the piercing tip end of a hollow needle permanently within the safety syringe body, protectively pressed against the inner surface of the tube, after a single use thus preventing the transmission of blood-borne pathogens, such as HIV/AIDS, hepatitis B, hepatitis C and other diseases, via needle reuse and accidental needle prickings with contaminated syringe needles.
Another object of the present invention is to provide a safety syringe apparatus that permanently prevents needle reuse or accidental needle prickings with contaminated syringe needles by providing a protective barrier between the hands and the hollow needle automatically and immediately after a single use and during disposal.
Another object of the present invention is to provide an automatically and immediately retractable needle safety syringe apparatus that is both efficient and effective at preventing the transmission of blood-borne pathogens and other diseases through needle reuse or accidental needle prickings with contaminated syringe needles.
Another object of the present invention is to provide an automatically and immediately retractable needle.safety syringe apparatus that is simple and inexpensive to manufacture, relative to the cost of manufacturing standard or conventional hypodermic needle syringes.
Another object of the present invention is to provide an automatically and immediately retractable needle safety syringe apparatus that is simple and self evident to operate and therefore requires no additional training to use the apparatus effectively and efficiently.
Another object of the present invention is to provide an automatically and immediately retractable needle safety syringe apparatus having a safety feature that is an integral part of the safety syringe, meaning that the safety feature is built-in as a necessary, inherent and integral part of the apparatus and is therefore not merely an accessory which might be removed, circumvented or overridden.